The present invention relates to an optical disk medium into and from which data are optically recorded and read out with use of an optical head, and also to a method and system for utilizing the optical disk medium.
In a conventional optical disk medium on which document data are to be digitally recorded, there has been employed such a method that ROM and RAM region bands are provided in inner and outer peripheral parts of the disk respectively, as disclosed, for example, in Japanese Patent Appln. Laid-Open Publication No. 61-280048. According to this method, in this way, the inner peripheral ROM region is located as separated from the outer peripheral RAM region. Thus, when it is desired to alternately and continuously read and write data in the ROM and RAM regions, this method requires an optical head to be moved or sought from the inner peripheral location to the outer peripheral location of the disk and thus requires a large head movement (seek) time.